Two component diazotype layers comprising a di-alkyl [piperazino-methyl]-phenol coupling compound



United States Patent 3 139,341 TWO COMPONENT liIAZOTYPE LAYERS COM- PRISLNG A DI-ALKYL[PIPERAZINO-METHYL]- THENOL COUPLING COMPOUND Heinz Schlesinger, Wiesbaden, Germany, assignor, by mesne assignments, to Keuifel & Esser (30., Hoboken,

.J. No Drawing. Filed Nov. 30, 1961, Ser. No. 156,117 Claims priority, application Germany Dec. 9, 1960 11 Claims. (Cl. 96-91) This invention relates to two component diazotype coatings and more particularly to the coupler used therewith so that copies made with the two component diazotype material of the present invention will be satisfactory for intermediate masters in making further copies.

It is known in diazotype copying that intermediate originals which are very satisfactory for further copying With these compounds, an improvement in covering power and in coatability and water resistance is nevertheless desirable.

The present invention relates to two-component diazotype coatings which are characterized in that they contain as coupler one or more compounds corresponding to the general formula R Ra where R and R represent branched and unbranched alkyl groups with up to five carbon atoms in a straight chain, where R is selected from the group consisting of hydrogen, alkyl, beta-hydroxyethyl, aralkyl, aryl, carboxyl, carbethoxy and carbpropoxy; and where R, is selected from the group consisting of hydrogen, branched and unbranched alkyl with up to five carbon atoms in a straight chain and carbethoxy.

Because of the powerful hydrotropic action of the substituted piperazinyl group the couplers according to the present invention coat very well onto conventional support or supporting material e.g., transparent paper. Also, the coupling products have increased water-resistance and produce high-contrast lines with a high degree of covering power. Even weak and thin lines are clearly reproduced.

Exposure times are short.

Because of these properties, the couplers according to the present invention are superior to the couplers used hitherto for similar purposes.

The substituted hydroxy dialkyl benzenes used in accordance with the invention as couplers in diazotype reproduction coatings are prepared by the Mannich condensation process by the reaction of dialkyl phenols with equimolecular quantities of formaldehyde and substituted piperazines.

Examples of suitable hydroxydialkyl benzenes for this reaction are: 2,5-dimethylphenol, 2,3-dimethylphenol, 3,5- dimethylphenol, 2,6-dimethylphen0l, S-methyl-S-ethylphenol, 2-methyl-5-isopropylphenol, 5-methyl-2-isopropylphenol, 3-methyl-6-ethylphenol.

The following are examples of the N-substituted piperice azines for this reaction: N-methyl-piperazine, N-hydroxyethyl-piperazine, N-ethyl-piperazine, N-benzyl-piperazine, N-phenyl-piperazine, piperazine-l-carboxylic acid ethyl ester, and piperazine-l-carboxylic acid propyl ester. These N-substituted piperazines can also be used: l-phenyl-Z- methyl-piperazine, 1-phenyl-2-ethyl-piperazine, l-phenyl- 3-ethyl-pipcrazine.

The couplers of the present invention couple with all the usual diazo components. The yellow to greenish yellow dyestuffs formed by the coupling of the couplers according to the invention with certain diazo compounds, in particular para-amino-diazo compounds, absorb light rays of so favourable a wave-length range that they have an exceptionally good covering power when used for further copying processes on light-sensitive materials. The copies formed are very high in contrast as a result of this increased covering power and are therefore particularly suitable for the preparation of intermediate originals. For example, drawings with weak lines can be reproduced with considerably greater clarity by the employment of the process according to the present invention than if intermediate originals prepared with previously known couplers were used.

It has further been found that the couplers in accordance with the invention are very suitable as adjuvants to other couplers for the production of brown and black tones.

The preparation of the compounds in accordance with the invention is described by a procedure below in which the parts by weight are in grams and the parts by volume are in milliliters.

98 parts by weight of 2,5-dimethyl-phenol are dissolved in 150 parts by volume of methanol. parts by volume of 30% formaldehyde are added and, with stirring and cooling, a solution of 130 parts by weight of N-phenylpiperazine in 70 parts by volume of methanol is introduced dropwise. After five hours stirring the solution is allowed to stand overnight after which the oil that has separated out crystallizes. The crystal slurry is ground with 100 parts. by volume of methanol and the liquid is removed by suction filtration. After recrystallization from 1500 parts'by volume of ethyl acetate, the crude product contains 74 parts by weight of pure 2,5-dimethyl- 4- [4-phenyl-piperazino-(1')-methyl]-phenol with a melting point of 184-185 C. Impure 2,5-dimethyl-6-[4- phenyl-piperazino-(1')-methyl] phenol crystallizes from the ethyl acetate mother liquor as a by-product; this melts at 133-134 C. after recrystallization from ethanol. the constitution of the two isomers can be checked by catalytic hydrogenation with copper chromoxide catalyst at about atmospheres and C. The condensation product with a melting point of 184-185 C. gives 2,4,5-trimethyl phenol (melting point: 71-72 C.) while the product with a melting point of 133-134 C. gives 2,3,6-trimethyl-phenol (melting point: 63-64" C.).

The other compounds according to the invention were prepared in an analogous manner with slight modifications where necessary in the type and quantity of solvent used depending on the solubility of the reaction partners. The compounds were isolated and used either as free bases or in the form of their salts. The following are listed as further compounds in accordance with the invention:

( 1) 2,6-dimethyl-4-[4-phenyl-piperazino-(1)-methyl]- phenol (melting point: 114 C.).

(2) 3,5-dimethyl-2-[4-methyl-piperazino-( 1' -methyl]- phenol (melting point: 99-100 C.).

(3 2,5 -dimethyl-4- [4'-methyl-piperazino-( 1 -methyl] phenol (melting point: 174175 C.).

(4) 2,3-dimetl1yl-6-[4'-phenyl-piperazino-(1')-methyl]- phenol (melting point: 142-143" C.).

(5 2,5 -dimethyl-4- [4'- 3-hydroxyethyl-piperazino-(1')- methyl]-phenol (melting point: 136137 C.).

(6) 2,5-dimethyl-4- [4'-benzyl-piperazinol -methyl] phenol (melting point of the hydrochloride: 237 C. with decomposition).

(7) 3-methyl-6-isopropyl-4- [4'-methyl-piperazino-( 1 methyl]-phenol (melting point of the hydrochloride: 213-214 C. with decomposition).

( 8) 3-methyl-5-ethyl-2- [4-phenyl-piperazino- 1' methyl1-phenol (melting point: 118 C.).

(9) 2,6-dimethyl-4- [4'-benzyl-piperazino-( 1 -methy1] phenol (melting point: 151l52 C.).

( 10) 3,5 -dimethyl-2- [2-carbethoxy-piperazino- 1 methyl1-phenol (melting point: 92 C.).

(1 l) 2,5-dimethyl-4-[4'-ethyl-piperazino-( 1)-methyl] phenol (melting point of the hydrochloride: 217- 218 C. with decomposition).

( 12) 2,6-dimethyl-4- [4'-B-hydroxyethyl-piperazino-( 1')- methyl]-phenol (melting point: 136-137 C.).

( 13 2,6-dimethyl-4-[3'-methyl-4-phenyl-piperazino- 1 methy1]-phenol (melting point of the hydrochloride:

' 181182 C. with decomposition).

( 14) 2,6-dimethyl-4- [4'-carbethoxy-piperazino-( l)- methyl]-phenol (melting point: 114115 C.).

(15 2,5-dirnethyl-4- [4'-carbethoxy-piperazino-( 1' methyl]-phenol (melting point: 101-102 C.).

(16) 3,5-dimethyl-2- [4'-carbpropoxy-piperazino-( l methylj-phenol (melting point: 74 C.).

( l7) 2,-6-dimethyl-4- [4'-carbpropoxy-piperazino-( 1) methyH-phenol (melting point of the sulphate: 201-202 C. with decomposition).

(18) 2,5 -dirnethyl-4- [4'-carbpropoxy-piperazino-( 1' methyl]-phenol (melting point of the sulphate: 181-183 C. with decomposition).

Couplers which form dyestuffs of most favorable opacity are 2,5-dimethyl-4-[4'-phenyl-piperazino-(1)-methyl]-phe not and those compounds which in the above list are numbered 1, 3, ll, 14, 15, and 17.

Example 1 An acetyl cellulose foil was coated with a solution of the following composition: 45 parts by volume of ethylene glycol monomethylether, 45 parts by volume of methyl ethyl ketone, 10 parts by volume of Water, 1.5 parts by weight of citric acid, 1.6 parts by weight of boric acid, a 0.6 part by weight of sulphosalicylic acid, 4.5 parts by weight of 3,5-dimethyl-2-[4'-methylpiperazino-(l')-methyl]-phenol and 4.0 parts by weight of the diazo compound from 1-amino-3-methyl-4-N-ethylaminobenzene in the form of the fluoborate. After the coating was dried, it was exposed behind a master to a 12-amp. arc lamp and developed with ammonia gas in the usual manner. The prints obtained had a yellow shade and were suitable as intermediate originals.

Example 2 a A solution of 4.5 parts by weight of 2,6-dimethyl-4-[4'- carbethoxy-piperazino-(1)-rnethyl]-phenol, 1 part by volume of concentrated pure hydrochloric acid, 6 parts by weight of citric acid, 3 parts by weight of boric acid, 2 parts by weight-of aluminum sulphate and 4 parts by weight of the diazo compound from 1-amino-4-morpholino benzene in the form of the zinc chloride double salt in 100 parts by volume of Water was coated in the normal manner upon transparent paper and the coating dried. After the material had been exposed behind a master to a 12-amp. carbon arc lamp, it was developed with ammonia gas. The prints, which were yellow in colour, were used as intermediate originals for the preparation of further copies.

Example 3 The procedure described in Example 1 was followed but the 4.5 parts by weight of 3,5-dimethyl 2-[4' methylpiperazino-(l)-methyl]-phenol were replaced by 4 parts by weight of 2,5-dimethyl-4-[4'-ethyl-piperazino-(1')- methyl]-phenol-hydrochloride. The resulting prints had good properties for further copying purposes.

Example 4 The coating solution had the same composition as that described in Example 2, but the coupler was replaced by 4.2 parts by weight of 2,5-dimethyl-4-[4'-phenylpiperazino( 1' -methyl] -phenol.

Example 5 A solution of the following composition was coated upon an opaque paper: 6 parts by weight of citric acid, 3 parts by weight of boric acid, 4.5 parts by weight of thiourea, 15 parts by volume of isopropyl alcohol, 2 parts by weight of 2,5-dimethyl-4-[4-methyl-piperazino-(1)- methy1]-phenol, a 0.6 part by weight of 2-hydroxynaphthalene-3,6-disulphonic acid (sodium salt), and 2 parts by weight of the diazo compound from 1-amino-4- morpholino-benzene in the form of the zinc chloride double salt in parts by volume of water.

After the coating had dried it was exposed in the usual manner to a 12-amp. arc lamp and developed with gaseous ammonia. The resulting prints had a light brown shade. When a transparent paper was used as base, the prints were usable as intermediate originals. From the above description it Will be apparent that applicant has provided a new coupler for diazo type materials which gives clear lines in a copy of sufficient density for making further copies from the copy used. The copy made with the diazo coating including the coupler of the present invention provides a most satisfactory intermediate master for making additional copies.

It will be apparent that changes may be made within the scope of the invention as defined by the valid interpretation of the claims.

What is claimed is:

1. A two-component diazotype coating comprising a light-sensitive diazonium compound and an azo coupling component, said coupling component being 2,5-dimethyl- 4-4'-phenyl-piperazino- 1' -methyl-phenol.

2. A two-component diazotype coating composition comprising a light-sensitive diazonium compound and an azo coupling component having the general formula:

R1 R2 R4 CHE-N N-R3 where R and R are alkyl groups having up to five carbon atoms in a straight chain, R is a member selected from the group consisting of hydrogen, methyl, ethyl, phenyl, benzyl, beta-hydroxyethyl, carbethoxy, and carbpropoxy, and R is selected from the group consisting of hydrogen and methyl.

3. A two-component diazotype coating composition comprising light-sensitive diazonium compound and 2,6- dimethyl-4- [4'-phenyl-piperazino-( 1')-methyl] -phenol.

4. A two-component diazotype coating composition comprising light-sensitive diazonium compound and 3,5- dimethyl-2- [4-mefihyl-piperazino-(l)-methyl] phenol.

5. A two-component diazotype coating composition comprising light-sensitive diazonium compound and 2,5- dimethyl-4- [4'-methyl-piperazino-(l )-methyl] phenol.

6. A two-component diazotype coating composition comprising light-sensitive diazonium compound and 2,3- dimethyl-6- [4'-phenyl-piperazino-(1)-methyl] -phenol.

7. A two-component diazotype coating composition comprising light-sensitive diazonium compound and 2,5- dimethyl 4- [4 beta hydroxyethyl piperazino (1), methyH-phenol.

8. A two-component diazotype coating composition comprising light-sensitive diazonium compound and 2,5- dimethy1-4- [4-ethyl-piperazino-( 1 -methyl] -pheno1.

9. A two-component diazotype coating composition comprising light-sensitive diazonium compound and 2,6- dimethyl 4 [4 carbethoxy piperazino-(1')-methyl]- phenol.

10. A two-component diazotype coating composition comprising light-sensitive diazonium compound and 2,5- dimethyl 4-[4' carbethoxy piperazino (1')-methyl]- phenol.

11. A two-component diazotype coating composition comprising light-sensitive diazonium compound and 2,6-

6 dimethyl 4 [4 carbpropoxy-piperazino-(1)-methy1]- phenol.

References Cited in the file of this patent UNITED STATES PATENTS 2,415,786 Buck et a1. Feb. 11, 1947 2,467,358 Neumann Apr. 12, 1949 2,537,106 Von Glahn et a1 Jan. 9, 1951 2,767,186 Baltzly et a1. Oct. 16, 1956 2,882,271 Janssen Apr. 14, 1959 2,946,684 Sus et a1. July 26, 1960 8,028,240 Werner et a1 Apr. 3, 1962 

2. A TWO-COMPONENT DIAZOTYPE COATING COMPOSITION COMPRISING A LIGHT-SENSITIVE DIAZONIUM COMPOUND AND AN AZO COUPLING COMPONENT HAVING THE GENERAL FORMULA: 